Heat shielded sealing curtain

ABSTRACT

A sealing curtain for a loading dock includes a pliable heat shield that helps protect the sealing curtain from concentrated heat generated by a truck&#39;s taillight being pressed against the sealing curtain. The heat shield is preferably placed just underneath a sealing surface of the sealing curtain. The heat shield reflects heat away from an inner surface and disperses the heat over a broader area to reduce the peak temperature of any hot spots. The sealing curtain may be height adjustable to position the heat shield at various heights along the loading dock.

CROSS REFERENCE TO RELATED APPLICATION

This application is a continuation of U.S. patent application Ser. No.10/369,973 entitled “Heat Shielded Sealing Curtain,” filed Feb. 20,2003, which is a continuation-in-part of U.S. patent application Ser.No. 09/548,876, filed Apr. 13, 2000, both of which are incorporatedherein by reference in their entirety.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The subject invention generally pertains to a loading dock and morespecifically to a dock seal disposed around a doorway of the dock.

2. Description of Related Art

When an exterior doorway of a building is used as a loading dock forvehicles, especially trucks, the perimeter of the doorway may include aloading dock shelter. The shelter may be formed of rigid or compressibleheader and side panels. Head curtains and side curtains, referred tocollectively as sealing curtains, are typically used over these panelsto seal-off gaps that would otherwise exist between the exterior face ofthe building and the back end of the truck. Such sealing allows cargofrom the rear of the truck to be loaded and unloaded while thedockworkers and the cargo are protected from the weather. The headerpanel runs horizontally across the top of the doorway and the sidepanels run vertically along each lateral edge of the doorway. Sealing isprovided by backing the truck up against the shelter, so that thecurtains sealingly engage the vehicle as it is backed-up.

Constant usage damages the external surfaces of dock shelters and thesesealing curtains. The curtains, for example, are exposed to harshweather conditions, made even harsher by fluctuations in weatherconditions. Additionally, the curtains are ofttimes exposed to intenseheat during normal operation due to the taillights on trucks. Thisexposure occurs when taillights, located along the upper rear edge ofthe truck, push against the sealing curtain or dock shelter. Thetaillight problem is increasingly more prevalent, as the NationalHighway Traffic Safety Administration (NHTSA) has recently issuedinterpretative rules/communications regarding Federal Motor VehicleSafety Standard No. 108. FMVSS-108 requires a cluster of threeidentification lamps to be mounted as close as practicable to the top oftruck vehicles. These lights are ideally placed at the extreme height ofthe vehicle and are used to identify the vehicle to other motorvehicles.

The lights are often placed in the upper, back corners of truck beds andcan create intense heat concentrations that over time will damage dockshelters and sealing curtains, in particular sealing curtains. Thelights may be turned off during loading and unloading. But if the truckoperator inadvertently leaves the lights on, the outer surfaces of thedock shelter or sealing curtain will absorb the heat generated by thesetaillights. The excessively high temperatures that result will wear onthe structures, degrading their appearance. More importantly, the hightemperatures may crack the structures and, in some extreme cases, mayeven cause the structures to burn or melt at the points of contact.

It is, therefore, desirable to have sealing curtains that can withstandintense heat and still offer other desirable features such asresiliency, lightweight, appearance, etc.

SUMMARY OF THE INVENTION

In order to provide a sealing curtain that can tolerate heat generatedby a vehicle's taillight, a sealing curtain comprising a sealing surfacefor engaging the parked vehicle; and a heat shield adjacent the sealingsurface, wherein the heat shield and the sealing surface are pliable andwherein the heat shield has a higher thermal conductivity than thesealing surface to dissipate heat from the parked vehicle across thesealing curtain.

In some embodiments, a heat shield is positioned adjacent a sealingsurface to protect the sealing curtain from heat damage.

In some embodiments, a sealing curtain is provided with a heat shieldthat has appreciable thermal conductivity to help disperse heat.

In some embodiments, a sealing curtain is provided with a heat shieldthat has appreciable reflectivity to reflect some heat away from aninner surface of the sealing curtain or to reflect some heat away from amaterial behind the sealing curtain.

In some embodiments, a sealing curtain is provided with a heat shieldthat can withstand a higher temperature than a sealing surface of thesealing curtain, whereby the heat shield helps protect the sealingcurtain from heat damage.

In some embodiments, a sealing curtain is provided with a leading edgethat is height adjustable.

In some embodiments, the sealing curtain includes an armor pleat at itsedges.

In some embodiments, the sealing curtain includes a head curtain thatruns substantially horizontally.

In some embodiments, the sealing curtain includes a side curtain thatruns substantially vertically.

In some embodiments, a sealing surface of a sealing curtain includesraised elements that assist in heat dissipation across the sealingcurtain.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a perspective view of a dock pad that includes a heat shield.

FIG. 2 is a cross-sectional view taken along line 2-2 of FIG. 1.

FIG. 3 is a cross-sectional view similar to that of FIG. 2, but ofanother embodiment.

FIG. 4 is a perspective view of an example sealing curtain that includesa heat shield.

FIG. 5 is a perspective view of the sealing curtain of FIG. 4 showingadditional detail.

FIG. 6 is a perspective view of an example sealing curtain having anadjustable height.

FIG. 7 is a perspective view of an example structure having a sealingcurtain of an adjustable height with two side curtains of separatelyadjustable height.

FIG. 8 is a perspective view of an example side curtain having a heatshield.

FIG. 9 is a front view of the structure of FIG. 8 showing support strutsin the side curtains.

DESCRIPTION OF THE PREFERRED EMBODIMENT

To create a weather seal between the rear of a truck 10 (or some othervehicle) and the perimeter a loading dock doorway 12, a dock pad 14 (ordock pad assembly) is installed, as shown in FIG. 1. In this example,dock pad 14 includes a side pad 16 mounted along each lateral edge ofdoorway 12, and a top or head pad 18 installed along the doorway's upperedge. Pads 16 and 18 are resiliently compressible, so as truck 10 backsup against them, the pads compressively and sealingly conform to thecontour of the truck's rear edges.

To provide dock pad 14 with durability and resilient compressibility,pad 14 includes a resiliently compressible foam core 20 covered by atough outer cover 22, as shown in FIG. 2. In this example, core 20consists of a polyurethane or foamed polyester, such as, for example, anL24 open-cell polyurethane foam provided by Leggett & Platt of Carthage,Mo. It should be appreciated by those skilled in the art; however, thata wide variety of other synthetic or natural foams may also work well.In some embodiments, cover 22 is a 3022_MFRLPC_DC7 material provided bythe Seaman Corporation of Wooster, Ohio. Other examples of covermaterials would include, but are not limited to, HYPALON, canvas duck,rubber-impregnated fabric, and coated nylon fabric.

In assembling pad 14, cover 22 wraps at least partially around core 20,and the two are attached to a relatively rigid backer 24, such a formedsteel channel or a wood board. Backer 24, in this example, provides amounting surface 26 that facilitates the installation of pad 14. Aconventional fastener or anchor can be used to attach backer 24 to awall 28 of a loading dock 30. In some embodiments, cover 22 attaches tothe side edges of backer 24 by any one of a variety of fastenersincluding, but not limited to, screws, VELCRO, rivets, hooks, andadhesive. Core 20 can be frictionally held to cover 22, or the two canbe joined in a more positive manner. For example, cover 22 can beconnected to core 20 with adhesive, straps, hooks, VELCRO, stitches,screws, etc.

To make pad 14 more resistant to heat, such as heat generated by ataillight 32 pressing against certain points 34 on a sealing surface 36of pad 14, a heat shield 38 is attached to pad 14. In some embodiments,heat shield 38 is incorporated within a Commercial Material RTCM01,which consists of two flexible sheets or layers of perforated aluminumfoil reinforced with a polyethylene scrim or fabric, as provided byRadiant Technology, of Dallas, Tex. The flexibility of shield 38 ispreferably sufficient to allow dock pad 14 to compressively conform tothe contour of the truck's rear edges and then decompress to the pad'soriginal shape. Heat shield 38 can be attached to pad 14 using adhesive,friction, hooks, straps, stitches, and/or various other fasteners.Shield 38 can be attached to the exterior or interior of pad 14,however; shield 38 is preferably installed between cover 22 and foamcore 20 for structural, functional, and aesthetic reasons.

Placing shield 38 underneath cover 22, helps keep cover 22 exposed tothe outside, thus taking advantage of the cover's toughness, weatherresistance and pliability. Moreover, shield 38 preferably has a higherreflectivity than core 20 and cover 22. This can be beneficial in caseswhere the cover can withstand a higher temperature than the core,wherein “withstand a higher temperature” means a material can be raisedto the higher temperature and then substantially recover its originalproperties after its temperature returns to normal. For example, if thefoam of core 20 has an auto ignition point (i.e., temperature at whichthe material self-ignites without being triggered by a spark or a flame)of 700 degrees Fahrenheit and cover 22 has an auto ignition point of 900degrees, then heat shield 38 with high reflectivity could reflect heataway from the foam and redirect it into cover 22, which may be able tohandle the heat better. In some embodiments, both cover 22 and core 20have a lower auto ignition point than heat shield 38 (e.g., when shield38 is one of the two layers of aluminum foil contained within CommercialMaterial RTCM01).

To reduce peak temperatures of core 20 and/or cover 22 when heated bytaillight 32, heat shield 38 is made of a material that has a higherthermal conductivity than core 20 and/or cover 22. The maximumtemperature at areas of concentrated heat, such as points 34, is reducedby shield 38 being able to effectively disperse the heat over a broaderarea. The term, “thermal conductivity” refers to a material's ability toconduct heat of a given temperature gradient along a given length andthrough a given cross-sectional area of the material, thus thermalconductivity is a property of the material itself, and is generallyindependent of the material's shape. A typical unit of measure forthermal conductivity would be (Btu)/(hr)(ft)(° F.).

To provide even greater heat protection, another embodiment, similar tothat of FIG. 2, provides a dock pad 14′ with two heat shields 38′, asshown in FIG. 3. It is believed that additional heat protection isprovided by the additional overall thickness of the two shields andperhaps partially provided by virtue of an additional slight airinterface 40 that may exist between the two shields 38′. Moreover, for agiven total thickness, two individual shields instead of one relativelythick one is more flexible, just as a stack of individual cards is moreflexible than a stack of cards whose faces are glued together.

A strap 42 inserted through a slit 44 in foam core 20′ helps hold thetwo shields 38′ in place. A loop 46 at each end of strap 44 engagesholes 48 in shields 38′; however, strap 42 could attach to shields 38′in a variety of other ways as well. Also, strap 42 could feed around theback of core 20′ to eliminate the need for slit 44; however, strap 42extending through slit 44 helps keep strap 42 and shields 38′ fromshifting along the length of a pad.

To provide even greater heat protection, FIGS. 4 and 5 show anembodiment with a sealing curtain 50 (a head curtain, in thisillustration) that has an integral heat shield. The sealing curtain 50is installed around a loading dock doorway 52, partially covering sidepads 54. The sealing curtain 50 may be adapted for retrofitting ontoexisting dock pads, extending over an existing head pad and side panels.The sealing curtain 50 includes two armor pleat sections 56 and 58 atthe outer sides of the sealing curtain 50. The armor pleats 56 and 58are formed of a series of overlapping sections 60 and 62, respectively.The armor pleats 56 and 58 may be positioned to coincide with the edgesof the sealing curtain 50. The edges of the truck, where intense lightsare disposed, typically contact the sealing curtain 50 at the armorpleats 56 and 58, which provide additional abrasion protection when thetruck is backed into and away from the doorway 52. Additional pleats maybe employed extending down the length of the side panels 54 to offerfurther protection. The overlapping sections 60 and 62 reduce abrasionwear not only because of extra layering, but also because sections aremovable relative to one another.

In addition to pleats, the side panels 54 may each include heat shieldlayers, for example, if the side panels 54 are side pads formed ofcompressible foam cores that are susceptible to heat damage.

The sealing curtain 50 includes a middle section 64 extending betweenthe armor pleats 56 and 58. The middle section 64 is formed of an outer,sealing surface 66 and an inner surface 68, as shown in FIG. 5.Sandwiched between surfaces 66 and 68 is a heat shield 70. The heatshield 70 may be any of the materials described with respect to otherexamples described herein. The heat shield 70 preferably has a higherheat reflectivity than the sealing surface 66 and the inner surface 68.Therefore, the head shield 70 will not only protect covered structures,like head panels or side panels, it will also protect the sealingcurtain 50 itself.

The material of the heat shield 70 may have a higher thermalconductivity than the surfaces 66 and 68, as described above, as well.As a higher thermal conductivity material, the heat shield 70 willdisperse heat from the high-temperature points where a taillight abutsthe sealing curtain 50. Dispersing heat through a high thermalconducting material will greatly decrease the likelihood that thesealing curtain 50 will be damaged at these hot spots. High thermalconductivity materials, like aluminum-based materials, are preferred,due to their durability, resistance to deformation over time, structuralsupport, and flexibility. As with heat shield 38, the heat shield 70 maybe attached to the sealing curtain 50 using adhesive, friction, hooks,straps, stitches, and/or various fasteners. Also, the heat shield 70 mayalternatively be attached at the exterior of the surface 66 exposed toan on-coming truck.

Further still, the heat shield 70 may comprise multiple layers or sheetsthat individually or collectively provide heat shielding. For example,the heat shield 70 may be a heat trapping structure sandwiched betweenthe surfaces 66 and 68. The heat shield 70 preferably extends from armorpleat 56 to armor pleat 58, so as to provide heat shielding againsttaillights that may contact at any point on the sealing curtain 50. Theheat shield 70 may also extend under the armor pleats 56 and 58 to addfurther protection at these locations. A heat shield may also beintegrated into each of the overlapping sections 60 and 62, if sodesired, such that each pleat has a separate heat shield layer.

To further shield the sealing curtain 50 from heat damage, the sealingsurface 66 may be embossed with a pattern of raised elements 72. Theraised elements 72 may be patterned with sufficient spacing betweenadjacent elements to further dissipate the heat from a taillight over anumber of contacts points. A checkerboard pattern is preferred, thoughvarious patterns and various raised elements may be used.

FIG. 6 shows an example sealing curtain 50′, which is similar to that ofsealing curtain 50 and which is height adjustable so that it mayoverhang a desired amount from the top edge of the loading dock doorway52. The sealing curtain 50′ overhangs upper portions of the side panels54′, as well. To adjust the sealing curtain 50′, a rod 74 is placed at aleading edge 76 of the curtain 50′. The rod 74 may be attached to theleading edge 76 by overlapping a portion of the sealing curtain 50′ ontoitself forming a slot for receiving the rod 74. The rod 74 providesrigidity and preferably extra weight to allow the sealing curtain 50′ tobe pulled by a series of ropes 78, 80, 82. The ropes 78, 80, and 82 maybe part of a single rope or part of a rope pulling mechanism and eitherway are used to raise and payout the leading edge 76. The rod 70 may beweighted to bias the sealing curtain 50′ to fall upon release of tensionin the ropes 78, 80, 82. A counter-balancing weight may be used to biasthe sealing curtain 50′ to a certain height above the floor of thedoorway 52. In the illustrated example, the ropes 78, 80, and 82 areconnected through loops attached to a frame 84 that extends from thedoorway 52. The frame 84 includes parallel slats 86 and parallel slats88 and 90. The frame 84 may be part of a dock shelter, for example ahead panel of the same.

Other pulling mechanisms known to persons of ordinary skill in the artmay also be used for moving the sealing curtain 50′. For example, it maybe useful to use a chain in lieu of ropes, and it may be desirable touse either a manual pull mechanism or an automatic one.

Adjusting the position of the leading edge 76 allows the sealing curtain50′ to provide heat shielding for vehicles of various heights. Thus, thesealing curtain 50′ provides an adjustable-height heat shield for aloading dock. Preferably, the heat shield is formed of a material thatis flexible enough to pay out from a raised position and structurallyrigid enough to maintain its shape and properties in a lowered position.

Numerous alternatives to the examples shown may be used, for example,sectioning the sealing curtain 50′ so that a middle portion 64′ or anarmor pleat portion 56′ (not shown) 58′ are separately heightadjustable. FIG. 7 shows an example heat shielding structure 100 formedof a sealing curtain 101 having a head curtain 102, a first side curtain104, and a second side curtain 106, each individually height adjustable.The head curtain 102 is adjustable over a central portion of a doorway108 and, in the illustrated example, extends below a header panel 110that extends horizontally across the top of the doorway 108 adjacent twovertically extending side panels 112, 114. The head panel 110 and sidepanes 112, 114 may be rigid or compressible structures. The side curtain104 extends over the side panel 112, and the side curtain 106 extendsover the side panel 114. In the illustrated position, the side curtains104 and 106 have been extend below the height of the sealing curtain102. Also, in the illustrated example, the curtains 102, 104 and 106each have heat shields like the heat shield 70 described above. A heatshield 116, for curtain 104, is shown sandwiched between a sealingsurface 118 and an inner surface 120. The heat shield 116 preferably hasa higher heat reflectivity than the sealing surface 118 and the innersurface 120. The heat shield 116 may also have a higher thermalconductivity than the surfaces 118 and 120, as well. Further still, theheat shield 116 may comprise multiple layers or sheets that individuallyor collectively provide heat shielding. The head curtain 102 has a heatshield (not shown) like the heat shield 70 of FIG. 5. Any of thecurtains 102, 104, and 106 may have amour pleats or embossed raisedportions, as described above with respect to FIG. 5.

FIGS. 8 and 9 show an example of another application of a heat shield. Avehicle shelter 200 includes a head panel 202 and two side panels 204attached to an exterior wall face defining a doorway 206. Two side pads208 are attached to side panels 204 for example using a conventionalhook and loop attachment device 210 commonly referred to as Velcrofasteners. The loop portion of attachment device 210 may be attached toone of the side curtains 208 or the side panel 204 and the latch portionattached to the other of the side curtains 208 or the side panel 204,wherein the latch and loop portions may latchably engage each other andattach the side curtain 208 to the side panel 204. The side curtain 208and the side panel 204 may be selectively released by pulling the hookand loop portions apart.

The size, number and location of the attachment devices 210 may beadjusted to provide the proper support for the side curtain 204. It willbe appreciated that the side curtain 208 may be releasably connected tothe side panel 204 using snap fasteners, zippers or other methods knownto those skilled in the art. If desired the side curtain 208 may also befixedly attached to the side panel 204 using stitching or other methodsknown to those skilled in the art which would permanently affix the sidecurtain 208 to the side panel 204.

The side curtains 208 have heat shields 212 similar to heat shields 70described above. The heat shield 212 is sandwiched between a sealingsurface 214 and an inner surface 216 and may be formed of the materialspreviously described. In particular, the heat shield 212 preferably hasa higher heat reflectivity than the sealing surface 214 and the innersurface 216. The material of the heat shield 212 may have a higherthermal conductivity than the surfaces 214 and 216, as well. Furtherstill, the heat shield 212 may comprise multiple layers or sheets thatindividually or collectively provide heat shielding. The side curtains208 may include amour pleats, with or without heat shields, as well.

FIG. 9 shows the side curtains 208 with a plurality of substantiallyresilient stays 218 (shown in phantom) that provide additional rigidity,lateral support and shape to the side curtain 208 and which may beembedded in the side curtain 208 or slidably inserted into pocketsprovided in the side curtains 208. The stays 218 will resiliently biasthe side curtain 208 towards a substantially straight position.

Although the invention is described with reference to a these examples,it should be appreciated by those skilled in the art that variousmodifications are well within the scope of the invention. For example,other sealing curtains employing a heat shield may be used. The sealingcurtains, both sealing curtains and side curtains may be attached todock shelters, compressible dock pads, and the like, in ways other thanthose depicted. Moreover, the curtains may be used alone. The scope ofthe invention is to be determined by reference to the claims thatfollow.

1. A sealing curtain adapted to seal against a vehicle parked againstthe sealing curtain, comprising: a sealing surface for engaging theparked vehicle; and a heat shield adjacent the sealing surface, whereinthe heat shield and the sealing surface are pliable and wherein the heatshield has a higher thermal conductivity than the sealing surface todissipate heat from the parked vehicle across the sealing curtain.